Facile Conversion of syn ‐[Fe IV (O)(TMC)] 2+ into the anti Isomer via Meunier's Oxo–Hydroxo Tautomerism Mechanism
Facile Conversion of syn ‐[Fe IV (O)(TMC)] 2+ into the anti Isomer via Meunier's Oxo–Hydroxo Tautomerism Mechanism
复制标题
通过 Meunier 的氧代-羟基互变异构机制将顺式 -[Fe IV (O)(TMC)] 2 轻松转化为反式异构体
DOI：
10.1002/anie.201811454
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Que, Jr., Lawrence
中科院分区：
文献类型：
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作者：
Prakash, Jai;Sheng, Yuan;Draksharapu, Apparao;Klein, Johannes E. M. N.;Cramer, Christopher J.;Que, Jr., Lawrence
[FeIV（O）（TMC）]2+（TMC=四甲基环胺）的顺反异构体代表了第一对具有相同配体拓扑结构的合成非血红素氧合铁（IV）络合物，不同之处仅在于与铁中心结合的氧合单元的位置。这两种异构体先前已被表征。本文报道了在MeCN中，顺式异构体[FeIV（Osyn）（TMC）（NCMe）]2+（2）转化为反式异构体[FeIV（Oanti）（TMC）（NCMe）]2+（1），这种异构化反应在水的作用下得到促进，最容易用1H NMR和拉曼光谱进行监测。 事实上，当H218 O被引入到2中时，新生的1会产生18 O标记。这些结果提供了令人信服的证据的机制，涉及直接绑定的水moleculetrans的氧原子在2与随后的氧-羟互变异构，其纳入作为氧原子的1。TMC支持配体的非平面性质使得这种异构化是不可逆的转变，不同于它们的平面血红素对应物。
Thesynandantiisomers of [FeIV(O)(TMC)]2+(TMC=tetramethylcyclam) represent the first isolated pair of synthetic non‐heme oxoiron(IV) complexes with identical ligand topology, differing only in the position of the oxo unit bound to the iron center. Both isomers have previously been characterized. Reported here is that thesynisomer [FeIV(Osyn)(TMC)(NCMe)]2+(2) converts into itsantiform [FeIV(Oanti)(TMC)(NCMe)]2+(1) in MeCN, an isomerization facilitated by water and monitored most readily by1H NMR and Raman spectroscopy. Indeed, when H218O is introduced to2, the nascent1becomes18O‐labeled. These results provide compelling evidence for a mechanism involving direct binding of a water moleculetransto the oxo atom in2with subsequent oxo–hydroxo tautomerism for its incorporation as the oxo atom of1. The nonplanar nature of the TMC supporting ligand makes this isomerization an irreversible transformation, unlike for their planar heme counterparts.